1. Field of the Invention
This invention generally relates to an opener for irradiation capsules in which samples for irradiation are sealingly contained. More particularly, the invention relates to an opener which functions to open such capsules after irradiation of radiation.
2. Description of the Prior Art
In a nuclear reactor, irradiation of radiation onto a sample is usually conducted, with the sample sealingly or shieldingly enclosed within capsules of metal or synthetic resin material. After irradiation, such a capsule is opened so as to take the sample out of the capsule. The capsule, however, should not be touched directly by an operator, since radiation has been irradiated to the capsule. Accordingly, it is necessary for the operator to put the radiation contaminated capsule in a lead cell for the purpose of radiation shielding. Thereafter, the operator may open the capsule by remotely controlling a capsule opener by means of a manipulator so as to remove the sample from the capsule using a tool such as a tong.
Conventionally, openers for irradiation capsules are known in the art. An example of such openers is shown in FIG. 6. The illustrated opener includes drive rollers 100, 110 adapted to be rotated in the same direction so as to rotatively drive a capsule A, a lever 130 for pivotal movement around a pin 120, a roller cutter 140 attached to one of the longitudinal ends of the lever 130, a cam member 50 disposed adjacent to the longitudinal other end of the level 130 for actuating the lever 130 to cause the roller cutter 140 to force against the capsule A, and a motor (not shown) for rotatively driving the drive rollers 100, 110 and cam member 150. Reference numeral 160 in FIG. 6 indicates a cam follower attached to the longitudinal other end of the lever 130.
When it is intended to open the capsule A, the capsule is first clamped between the drive rollers 100, 110 and the roller cutter 140 and then the motor is energized. By this, the drive rollers 100, 110, as well as the cam 150, is rotated in the direction indicated by arrow in FIG. 6. Thus, the longitudinal other end of the lever 130 is pushed away by means of the cam 150, while, at the same time, the longitudinal one end of the lever is pivotally driven so as to approach the capsule A. Accordingly, the roller cutter 140 causes the capsule A to force against the drive rollers 100, 110 so as to be rotated by the drive rollers 100, 110, whereby the roller cutter 140 penetrates into the capsule A so as to open the capsule A.
It is true that the above opener may actuate to securely cut or sever the capsule A in the initial stage of cutting or opening of the capsule. In the final stage of cutting, however, the force acting on the capsule A so as to urge the capsule against the drive rollers 100, 110 tends to become insufficient to rotate the capsule A. Thus, there would be possibility in that the capsule A would not be cut or opened completely.
Further, it is possible for the sample enclosed within the capsule A to be damaged due to vibration caused from rotation of capsule A, when the sample is fragile or brittle in nature.
Furthermore, it is difficult to increase displacement or movable distance of the roller cutter 140 due to the use of the cam member 150. This restricts application of a particular opener to capsules having a diameter within a specific range. Thus, it is not contemplated for conventional opener to have flexibility or universality.